// Thud - a dynamic object-oriented language
// Copyright (C) 2009,2010 David H. Hovemeyer <david.hovemeyer@gmail.com>

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/*
 * InputStream.h
 *
 *  Created on: Dec 14, 2009
 *      Author: dhovemey
 */

#ifndef INPUTSTREAM_H_
#define INPUTSTREAM_H_

#include <cstddef>

class InputStream {
private:
	InputStream(const InputStream &);
	InputStream& operator=(const InputStream &);

public:
	InputStream();
	virtual ~InputStream();

	/**
	 * Read one byte.
	 * @return a byte of data, or -1 if EOF has been reached or an error occurred
	 */
	virtual int read() = 0;

	/**
	 * Read multiple bytes.
	 * Unless EOF is reached or an error occurs, will block until at least one
	 * byte of data is read.
	 *
	 * @param buf the buffer into which the bytes read should be stored
	 * @param n   maximum number of bytes to read
	 * @return    number of bytes read, or 0 if EOF has been reached or an error occurred
	 */
	virtual size_t read(void *buf, size_t n) = 0;

	/**
	 * @return true if the stream is at EOF, false otherwise
	 */
	virtual bool atEOF() = 0;

	/**
	 * @return true if an error occurred, false otherwise
	 */
	virtual bool error() = 0;

	/**
	 * Read exactly the given number of bytes.
	 * 
	 * @param buf the buffer into which the bytes read should be stored
	 * @param n   maximum number of bytes to read
	 * @return number of bytes read; will be less than n only if an error occurred
	 *         or if EOF was reached before all bytes could be read
	 */
	size_t readFully(void *buf, size_t n);
};

#endif /* INPUTSTREAM_H_ */
